Combining pectin and sunflower seed protein for the development of biodegradable films with potential application in food packaging

The packaging used for food products is mostly made of synthetic polymeric materials, especially plastics, which contribute significantly to greenhouse gas emissions and the contamination of terrestrial and aquatic environments. Given the growing demand for environmentally responsible solutions, biopolymers from renewable sources, such as carbohydrates and proteins extracted from agro-industrial wastes, are emerging as promising alternatives for the development of sustainable packaging materials. In this context, this study aimed to develop and characterize biopolymeric films formulated from isolated sunflower seed protein combined with commercial citrus pectin in different proportions. The films were prepared by casting and characterized in terms of their optical, barrier, and mechanical properties and thermal stability. Increases in the amount of pectin added led to increases in film luminosity. All the prepared films showed complete soil degradation after 10 days of exposure, except those with higher amounts of pectin (80 and 100%). The main results showed that there was no linear correlation between the pectin/protein ratio and barrier, mechanical or thermal properties. Nonetheless, the addition of pectin led to films that were more rigid and less flexible. Regarding oxygen and water vapor barrier properties, the film containing 80% protein and 20% pectin exhibited the lowest permeability values. It was concluded that it is feasible to produce films based on pectin combined with protein isolated from sunflower seeds, representing a sustainable alternative to conventional plastic packaging.